Circuit device, a method for manufacturing a circuit device, and a semiconductor module

Abstract

A circuit device includes a semiconductor substrate on which a circuit element is formed, an electrode formed on a surface of the semiconductor substrate, an insulating layer formed on the electrode, a second wiring layer formed on the insulating layer, and a conductive bump which penetrates the insulating layer and electrically connects the electrode and the second wiring layer. The conductive bump is such that the size of crystal grains in a direction parallel with the surface of the semiconductor substrate is larger than the size of crystal grains in a conduction direction of the electrode and the wiring layer.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2007-050757, filed on Feb. 28, 2007, the entire contents of which are incorporated herein by reference.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates to a circuit device, a method for manufacturing a circuit device, and a semiconductor module.[0004]2. Description of the Related Art[0005]In recent years, along with the on-going downsizing and functional sophistication of electronic devices, there has been an ever-growing demand for smaller circuit devices to be incorporated into electronic devices. One of known ways to meet such a demand is to narrow the pitch of external connection electrodes of a circuit device. But because of the size of solder bumps themselves used as the electrodes and the formation of bridges at soldering, there has existed a limit to the downsizing by narrowi...

AI Technical Summary

Benefits of technology

The present invention provides a technology for improving the connection reliability of wiring in a circuit device. This is achieved by improving the size of crystal grains in the direction parallel to the surface of the substrate compared to the size in the conduction direction of the first and second wiring layers. This reduces the area occupied by crystal grain boundaries at the surface where the conductor is in contact with the second wiring layer, which helps to prevent impurities or the like from entering the conductor. The conductor is formed in a rolled material with an improved rupture strength, and its side face formed at an obtuse angle with a face in contact with the substrate or formed in a way that the area of cross section in parallel with the substrate increases as it approaches the second wiring layer. This improves the connection reliability between the conductor and the second wiring layer. The semiconductor module and method for manufacturing a circuit device also include these improvements.

Problems solved by technology

But because of the size of solder bumps themselves used as the electrodes and the formation of bridges at soldering, there has existed a limit to the downsizing by narrowing the pitch of the external connection electrodes of a circuit device.

However, when the phosphorus-containing copper anode dissolves, not only copper but also phosphorus solves out into the liquid, so that the plating solution gets contaminated with phosphorus, and the phosphorus codeposits in a plating film.

As a result, the copper posts formed by this electrolytic plating has an increased degree of hardness because of the phosphorus contained as impurities, and thus they can present a problem of lowered connection reliability under stresses.

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